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1. Field of the Invention
The present invention relates to oil, water, and gas well drilling and production and to coal bed methane production. More particularly, the present invention relates to an improved method and apparatus for producing oil and gas from a well using a gas carrier/transport system to remove produced liquids and/or solids by altering the flow regime of the production fluids towards or into a flow regime in which gas is the continuous fluid (i.e. the rate of upflowing gas in the well is sufficiently high in comparison with liquid production flow to generate plug flow, slug flow, froth flow, foam flow, annular flow, spray flow, or mist flow.) This is accomplished by use of supplemental gas flow and/or stimulation of the production sands or coal bed gas flow with a reduced pressure drop across the well itself. This invention can be applied to any gas, oil, and/or water well with insufficient formation gas pressure to prevent liquid buildup within the well during production. The present invention also relates to an improved method and apparatus for producing heavy and paraffinic oil from a well using a heated gas carrier/transport system to remove produced liquids and/or solids by altering the flow regime of the production fluids towards or into a flow regime in which gas is the continuous fluid. This invention can also be applied to any oil and/or water (liquid) well as a means of enhancing the well""s production. The gas can be either hydrocarbon, non-hydrocarbon, or a mixture of the two.
2. General Background of the Invention
Several patents have issued that are directed to oil, water, and gas well production. Many patents are directed to xe2x80x9cgas liftxe2x80x9d technology. In such a xe2x80x9cgas liftxe2x80x9d situation, a relatively small volume of gas is bubbled through the up-flowing hydrocarbon or non-hydrocarbon liquid, typically aided by or using valves, check valves, plungers, mandrels, or other mechanical devices xe2x80x9cdownholexe2x80x9d which are typically high maintenance devices. Some even refer to the necessity for xe2x80x9cbottom of pipexe2x80x9d filters or screens to remove sand and silt from the production fluids in order to allow these mechanical devices to operate. Some refer to the use of such mechanical devices to minimize the, required xe2x80x9clift gasxe2x80x9d.
All of the designs known to applicant and using these mechanical devices are designed to convert the well production from the bubble flow regime to the plug flow regime by use of these devices, not by gas alone. An early example of such a system is described in the Walter Loomis patent, U.S. Pat. No. 1,554,444 entitled xe2x80x9cSystem for the Recovery of Mineral Oilsxe2x80x9d. The ""444 patent describes a system for causing produced hydrocarbon gas to be reintroduced into the oil well down through the casing, into a mixer, causing the gas to be mixed with the upflowing hydrocarbon liquid inside the production tubing. The heavier components of the hydrocarbon gas will dissolve under pressure back into the hydrocarbon liquid (probably including those hydrocarbonsxe2x80x94propane and heavier), while the rest become mixed back into the oil in a finely divided form. Such an introducing of hydrocarbon gases into the hydrocarbon liquid cause the specific gravity of liquids to be lowered, thus causing the xe2x80x9cliftxe2x80x9d. The lighter hydrocarbon gases are supposed to dissolve in the hydrocarbon liquid at the bottom of the well, enhancing the lift by reducing the specific gravity. As the pressure in the production tubing is reduced as the hydrocarbon liquid rises to the surface, the lighter hydrocarbon gases will return to the vapor phase and further enhance the lift effect. The Loomis patent directed to the need to lift hydrocarbon liquid and does not deal with the need to lift xe2x80x9cproduced waterxe2x80x9d.
U.S. Pat. No. 1,790,450 entitled xe2x80x9cMethod and Apparatus for Operating Oil Wellsxe2x80x9d discloses a system of a mechanical means for causing produced hydrocarbon gas to build up pressure beneath a rubber plug, which will periodically rise and effectively xe2x80x9cswabxe2x80x9d the liquid hydrocarbon up the well pipe. This patent describes one of the early pumping type gas lifts. It uses a rubber plug or piston in the production tubing to lift the liquids out of the well by gas pressure under the piston.
In U.S. Pat. No. 2,005,7671 issued to Zublin, there is disclosed a system for causing produced hydrocarbon gas to be mechanically and centrifugally separated from the hydrocarbon liquid down in the well pipe, the gas being returned to the formation and the oil being produced containing a minimum amount of gas.
U.S. Pat. No. 2,034,798 entitled xe2x80x9cMethod of Flowing Wellsxe2x80x9d discloses a system for causing produced hydrocarbon gas by multiple wells to be stored up, and possibly be pressure boosted for proper usage, and to be used as motive gas for depleted wells in the same area.
U.S. Pat. No. 3,090,316 issued to Norman Montgomery and entitled xe2x80x9cGas Lifting Systemxe2x80x9d describes a system for causing produced hydrocarbon gas to lift a plurality of plungers throughout the production tubing, thus reducing the amount of time lost waiting for the plunger to return to the bottom for trapping new volume of lift gas.
U.S. Pat. No. 3,215,087 issued to Harry O. McLeod, Jr. and entitled xe2x80x9cGas Lift Systemxe2x80x9d describes a system for using gas injection, combined with intermittent slugs of a liquid which is both immiscible with the liquid being lifted from the well and does not adhere to the walls of the tubing and casing. This reduces the amount of liquid slippage by the slugs of lift gas.
U.S. Pat. No. 3,873,238 entitled xe2x80x9cMethod and Apparatus for Flowing Crude Oil from a Wellxe2x80x9d, issued to Johnnie A. Elfarr, describes a system for causing steam and/or air to be pumped down into an older formation, whose formation pressure has been depleted, artificially boosting the formation pressure and causing the hydrocarbon liquid to flow upward toward the surface. Steam is especially beneficial as the oil viscosity is high, becoming reduced by the elevated temperature caused by the steam. This system uses multiple downhole valves to effect the claims.
U.S. Pat. No. 4,223,724 issued to Carlo F. Levoni et al. and entitled xe2x80x9cDevice for Cleaning, Widening and Repairing Wells of Drinking Water and Irrigation Waterxe2x80x9d describes a system for cleaning, widening and repairing of a water well.
U.S. Pat. No. 4,275,790 issued to Bolling A. Abercrombie, entitled xe2x80x9cSurface Controlled Liquid Removal Method and System for Gas Producing Wellsxe2x80x9d describes a system for removal of accumulated production liquids. Assuming hydrocarbon gas is being produced from the well inside the casing, an internal production tubing, fitted with a loose fitting plunger, is used to periodically remove any collected liquids in the casing by shutting off the gas production while opening up the inner tubing, causing the gas to divert to the inner tubing, lifting the plunger and bringing the liquid up to the surface.
U.S. Pat. No. 4,345,64,7 issued to William C. Carmichael and entitled xe2x80x9cApparatus to Increase Oil Well Flowxe2x80x9d describes a system for attaching a pump to the top of the production pipe, thus causing a vacuum on the production oil. This production pipe goes down into an oil sump, lower than the producing sands in the well casing.
U.S. Pat. No. 4,390,061 issued to Charles short and entitled xe2x80x9cApparatus for Production of Liquid from Wellsxe2x80x9d describes a system for causing gas to enter the production tubing through an aspirator into the hydrocarbon liquid contained therein. The bottom of the production tubing should be fitted with a sand screen to prevent entrainment of sand particles. Further up the drill tubing are one or more check valves to prevent downward flow of liquid.
U.S. Pat. No. 4,410,041 issued to Davis et al. and entitled xe2x80x9cProcess for Gas-Lifting Liquid from a Well by Injecting Liquid into the Wellxe2x80x9d describes a system for sealing off any particular zone of the formation with remotely-actuable packers, and using gas to lift any produced hydrocarbons from this very zone. The primary purpose is for formation and drill stem testing.
U.S. Pat. No. 4,478,288 issued to Michael L. Bowyer and entitled xe2x80x9cApparatus with Annulus Safety Valve Through Tubing Injection and Method of Usexe2x80x9d describes a system for effecting safety control valving on both the gas supply line into the well casing and the return production tubing.
U.S. Pat. No. 4,480,697 entitled xe2x80x9cMethod and Apparatus for Converting an Oil Well to a Well with Effluent Raising by Gas-Liftxe2x80x9d, issued to Rene F. Goldaniga et al, describes a system for retrofitting an existing well, converting it to a gas lift system. Included in this patent is the required means for effecting the gas lift system while apparently providing superior flow shut-off capabilities.
U.S. Pat. No. 4,625,801 issued to Wayne C. McLaughlin et al. and entitled xe2x80x9cMethods and Apparatus for Recovery of Hydrocarbons from Underground. Water Tablesxe2x80x9d describes a system for using compressed air to lift hydrocarbon-contaminated groundwater up for collection and recovery.
U.S. Pat. No. 4,711,306 issued to Roy A. Bobo and entitled xe2x80x9cGas Lift Systemxe2x80x9d describes a system for mixing pressurized injection gas with pressurized injection liquid, which is then pumped down the well, during which time the increase in pressure will cause the gas to become compressed. As this injection stream enters the production conduit near the bottom of the well bore, the gas will begin to expand, helping to lift the production fluid.
U.S. Pat. No. 4,787,450 issued to Gregory R. Anderson et al. and entitled xe2x80x9cGas Lift Process for Restoring Flow in Depleted Geothermal Reservoirsxe2x80x9d describes a system for causing a gas lift process in a geothermal well.
U.S. Pat. No. 4,844,156 issued to Frank Hesh entitled xe2x80x9cMethod of Secondary Extraction of Oil from a Wellxe2x80x9d describes a system for repeatedly pressuring (super atmospheric) and depressuring (sub-atmospheric) the well formation by use of a sealed well casing.
U.S. Pat. No. 5,033,550 issued t Kenneth J. Johnson et al. and entitled xe2x80x9cWell Production Methodxe2x80x9d describes a system, targeted specifically at the coal bed methane production, causing lift gas to be fed down injection tubing to a side pocket mandrel and then to a gas lift valve. The objective is to reduce the bottom hole pressure low enough so that the methane gas, impregnated into the coal fines, will be released and carried up by the lift gas to the well head.
U.S. Pat. No. 5,211,242 issued to Malcolm W. Coleman et al. entitled xe2x80x9cApparatus and Method for Unloading Production-Inhibiting Liquid from a Wellxe2x80x9d describes a system for collecting liquids in a chamber down in the well casing, to which two tubing strings are connected; Volumes of the liquid are intermittently lifted out of the well through one of the tubing strings in response to high pressure gas injected into the other tubing string.
U.S. Pat. No. 5,377,764 issued to Alfred R. Jennings, Jr. and entitled xe2x80x9cMeans of Injecting CO2 into Circulation Tubing to Facilitate CO2 Gas Liftxe2x80x9d describes a system for introducing carbon dioxide gas into a viscous hydrocarbon heavy oil in the bottom casing of the well, allowing the carbon dioxide to dissolve in the oil, reducing it""s viscosity and density, thus allowing the less viscous oil to be lifted up the production tubing by means of the gas lift effect with carbon dioxide.
A system for introducing carbon dioxide gas into a viscous hydrocarbon heavy oil in the bottom casing of the well, allowing the carbon dioxide to dissolve in the oil, reducing it""s viscosity and density, thus allowing the less viscous oil to be lifted up the production tubing by means of the gas lift effect with carbon dioxide is described in U.S. Pat. No. 5,337,828, xe2x80x9cUse of Carbon Dioxide for Gas-Lifting Heavy Oilxe2x80x9d, issued to Alfred R. Jennings, Jr.
A system for effecting a formation flooding to drive hydrocarbons up to the surface in a well is described in U.S. Pat. No. 5,345,655 issued to Bruno Bernhardt, entitled xe2x80x9cMethod of and Arrangement for Obtaining Liquids and/or Gases from Ground or Rock Layersxe2x80x9d.
U.S. Pat. No. 5,464,309 issued to Alfonso R. Mancini et al. describes a system for removing chemical contaminants from groundwater formations; it accomplishes this by a xe2x80x9ctube within a tubexe2x80x9d design, using one of the tubes to supply gas down to the underground site, while applying a vacuum to the other tube and lifting the contaminated water.
U.S. Pat. No. 5,501,279 issued to Arvind K. Garg et al. entitled xe2x80x9cApparatus and Method for Removing Production-Inhibiting Liquid from a Wellborexe2x80x9d describes a system for causing produced water to be removed from a wellbore by use of chambers, valves, and potentially retrievable wirelines. With two production tubes attached to the chambers, one transporting pressurized lift gas down to the wellbore and the other lifting the produced water and methane gas, the pressure at the wellbore can be lowered enough to cause the entrained methane to be released from the carbonaceous subterranean formation.
U.S. Pat. No. 5,547,021 issued to Dennis P. Raden and entitled xe2x80x9cMethod and Apparatus for Fluid Production from a Wellborexe2x80x9d describes a system for assisting in lifting produced hydrocarbon liquid and produced water by means of a vacuum applied to the top of the production tubing; in addition, could possibly supplement lift by providing a lift gas fed from another production tubing to the bottom of the well. This lift gas could also be supplied by delivering down the well casing or the casing/tubing annulus. He also claims usage of eductors and valves.
U.S. Pat. No. 5,620,593 entitled xe2x80x9cMulti-Stage In-Well Aeratorxe2x80x9d, issued t Joseph C. Stagner, describes a system for utilizing in-casing aeration to remove VOC""s from contaminated groundwater.
U.S. Pat. No. 5,634,522 entitled xe2x80x9cLiquid level Detection for Artificial Lift System Controlxe2x80x9d issued to Michael D. Hershberger describes a system for detecting the liquid level in the well production tube, thus aiding in the determination when artificial lift becomes necessary.
U.S. Pat. No. 5,671,813 issued to Paulo Cesar Ribeiro Lima, entitled xe2x80x9cMethod and Apparatus for Intermittent Production of Oil with a Mechanical Interfacexe2x80x9d describes a system foressentially xe2x80x9cpiggingxe2x80x9d oil out of a production tube xe2x80x9cloopxe2x80x9d by sending a mechanical interface down one tube, propelled by pressurized gas, and then up the other tube (which has collected some oil as a xe2x80x9csumpxe2x80x9d), eventually arriving back at the surface having delivered a slug of oil.
U.S. Pat. No. 5,735,346, entitled xe2x80x9cFluid Level Sensing for Artificial Lift Control Systemsxe2x80x9d and issued to James Robert Brewer, describes a system for determining the fluid level in a well casing for controlling artificial lift systems.
U.S. Pat. No. 5,816,326 issued to John P. Slater entitled xe2x80x9cUphole Disposal Tool for Water Producing Gas Wellsxe2x80x9d describes a system for pumping produced water up the casing by use of a mechanical device with multiple mandrels, utilizing production gas to cause the device to xe2x80x9cpumpxe2x80x9d.
U.S. Pat. No. 5,839,514, entitled xe2x80x9cMethod and Apparatus for Injection of Tubing into Wellsxe2x80x9d issued to Thomas C. Gipson describes a system for improved handling of xe2x80x9ccoiled tubingxe2x80x9d in and out of a well.
U.S. Pat. No. 5,893,414 issued to Vladimir M. Shaposhnikov et al. discloses a device for intensification of hydrocarbon production and a hydrocarbons production system.
U.S. Pat. No. 5,906,241 issued to Mehmet Pehlivan et al, entitled xe2x80x9cMethod for Bubbling Extraction of Groundwaterxe2x80x9d describes a system for lifting contaminated groundwater by placing a hole in the extraction pipe a short distance above the static groundwater table, thus causing a bubbling action to aid in the lift of the groundwater by an applied vacuum at the head of the pipe. It is also claimed that this bubbling gas aids in the stripping of contaminants from the groundwater.
U.S. Pat. No. 5,911,278 issued to Donald D. Reitz, entitled xe2x80x9cCalliope Oil Production System,xe2x80x9d describes a system for gas lifting oil from a well by using down-hole valve on the end of the production tubing, and either lifting the oil up some macaroni tubing, or by possibly using an optional plunger or other device to mechanically lift the oil up a production tube.
The present invention provides an improved method and apparatus for producing oil, gas, and/or water from a well. The method of the present invention utilizes a gas carrier/transport system to remove produced liquids and/or solids by altering the flow, regime of the production fluids towards or into a flow regime in which the gas is the continuous fluid. The rate of upflowing gas in the well is sufficiently high in comparison with liquid production flow to generate plug flow, slug flow, froth flow, foam flow, annular flow, spray flow, or mist flow. The method of the present invention is accomplished by use of supplemental gas flow and/or stimulation of the production sands or coal bed gas flow with a reduced pressure drop across the well itself. The present invention can be applied to any oil, gas and/or water well with insufficient formation gas pressure to prevent liquid buildup within the well during production. This invention can also be applied to any oil and/or water (liquid) well as a means of enhancing the well""s production.